The various embodiments described herein pertain generally to a transformable wheel.
The invention of wheels, which allow heavy objects to be moved easily, has led to the development of early civilizations. In the modern society as well, wheels are widely utilized as an indispensable component in everyday life. For example, wheels can be found in various applications, such as a car, a wheelchair, a baby stroller, a cart, and so forth, to provide convenience for living.
A generally circular wheel is very efficient when travelling on an even ground. When passing an obstacle, such as stairs, however, the circular wheel is not efficient. In particular, when using a wheelchair, a stroller or a cart, it takes a lot of force and effort for a user to pass an obstacle, such as stairs. Many attempts have been made to provide user convenience in such cases.
In this regard, Korean Patent Laid-open Publication No. 10-0546952 (entitled “Electric Wheelchair”) describes a wheelchair designed to have improved stair-climbing ability. In this wheelchair, the heights of the front wheels and the rear wheels can be adjusted independently. In addition, the wheelchair includes a lever that is driven by a motor to aid in climbing stairs. This configuration is characterized in that the heights and movements of the front wheels and the rear wheels are controlled by using two motors.
This prior art wheel equipment is, however, of a high price. Moreover, a great force is temporarily required when the wheelchair climbs the stairs by the lever, which tends to create safety issues.
Further, Korean Utility Laid-open publication No. 20-0307551 (entitled “Multi Shaft Wheel”) discloses a structure that combines typical wheels. With this structure of combined wheels, a greater force can be obtained as the wheels are rotated in a radius of rotation which is larger than a typical radius of rotation. This structure can be manufactured at a low cost and is deemed to provide improved stair-climbing ability. When this structure travels on an even ground, however, the combined two wheels come into contact with the ground, resulting in the generation of a great amount of friction between the wheels and the ground. Thus, as compared to a case of using a single wheel, this structure may cause a user to feel more fatigued.
Thus, it is desirable to have a wheel structure capable of passing an obstacle, such as stairs or a slope with a small force without suffering deterioration in travel ability on an even ground.